Oxidative stress (OS) is increasingly recognized as a dynamic disturbance of cellular redox networks rather than a simple imbalance between oxidants and antioxidants. In this context, ferroptosis and cuproptosis—two regulated and metal-dependent forms of cell death—emerge as key mechanisms linking OS to metabolic dysfunction, inflammation, and tissue injury. This review integrates findings from biochemical, lipidomic and metallomic studies to describe how lipid peroxidation (LPO), glutathione (GSH)–Glutathione Peroxidase 4 (GPX4) activity, ferritinophagy, copper-induced mitochondrial protein lipoylation, and altered communication between organelles generate distinct redox signatures across diseases. By examining cutaneous, metabolic, cardiovascular, infectious, neurodegenerative, and oncologic conditions, we outline the shared redox pathways that connect iron- and copper-dependent cell death to systemic inflammation, immune dysregulation, and chronic tissue damage. Common oxidative markers—such as oxidized phospholipids, lipid aldehydes including 4-Hydroxynonenal (4-HNE) and malondialdehyde (MDA), and systemic metal imbalance—are highlighted as potential indicators of disease severity and as emerging therapeutic targets. We also discuss innovative analytical tools, including redox lipidomics, metallomic profiling and artificial-intelligence (AI)-based classification approaches, which improve the characterization of redox vulnerability and may guide the development of precision redox therapies. Overall, ferroptosis and cuproptosis represent unifying mechanisms that connect OS to multisystem disease and provide new opportunities for diagnostic refinement and targeted antioxidant-based interventions.